A few weeks ago when bathing I noticed a small hard pea sized lump directly on my anus and I had a look with a mirror it is a black/blue colour.

I looked it up on the internet and found a website where somebody had reported something similar to me it said that it would go in a few weeks but its been a few weeks now and it hasnt gone down and I am in turmoil as i am too embarresed to go doctors and can not stop thinking that it must be cancer.

It is not painful in anyway please can you tell me what this is or do i really have to go to the doctors.